Sir petrol average is not 8-10km.
its 10-12km (city) in every well kept vitz 1st generation 4 cylinder, 2nd generation Vitz has a newer 3 cylinder engine with increased efficiency and is more environment friendly with a better aerodynamic shape, its fuel consumption must be even lower.
vitz is many times better then local cars (except 7th gen CIVIC), no matter you compare reliability, efficiency, braking, suspensions, Active (ABS, airbags) and passive safety (torsional rigidity, crash structure), road holding and interior comfort.
parts are expensive, but I never need one in 3 years (75K KMS), except for side mirrors and its assembly (stolen), which was still less expensive then a 2009 GLI.
after driving, all the below mentioned cars for 5-6 years, if I have to live with 1 one car, excluding the CA4 Accord, it would be definitely a Vitz or VTI (very tough decision though).
2005 Vitz 1.0L Auto (family car)
Accord CA4 1.6L Manual. (my car)
2005 GLI.(brother's car)
2007 Alto FF CNG (brothers car)
2005 Civic EXI PROSMATEC. (father's car)
2006 2.0D Saloon (office car)
you should reconsider, you will regret your decision.
A car should be owned on its merits not by opinions, besides local cars are so expensive that one cant even buy a new decently equipped Cultus in around 850K in these days.